If your talking about the (search thieves landing) requirement for the outfit. Its in that warehouse where you and Irish broke into (after sneaking across the roof) to get the Gatling gun. Its in the room you free the man from
In theives There's a warehouse with some boxes go to it in it in the top right corner there's what I would call the managers officE over looking it just go up the stairs and into that room and the should be a treasure chest there
For scrap 6 on the Bollards Twin Outfit, you're required to purchase at the tailor in Thieve's Landing. I purchased the Elegant Suit and I checked my outfits and there isn't an "X" on the last scrap. --- I wont change this sig until GameFaqs gets an "edit" button.